This clinical trial is focused on studying the long-term effects of a treatment called DNL310 in patients with Mucopolysaccharidosis Type II, also known as MPS II. MPS II is a rare genetic disorder that affects the body’s ability to break down certain complex molecules, leading to various health issues. The treatment being tested, DNL310, is a special type of protein designed to help manage the symptoms of MPS II. It is given as a solution through a vein, a method known as intravenous infusion.

The purpose of this study is to evaluate how safe and tolerable DNL310 is for patients over a long period. Participants in this study will receive the treatment and be monitored for any side effects or changes in their condition. The study will also look at how the treatment affects certain substances in the body, like glycosaminoglycans, which are complex sugars that build up in patients with MPS II. Additionally, the study will assess changes in physical abilities, such as walking distance, and organ sizes, like the liver and spleen, using imaging techniques like MRI.

This study is an extension of previous research, meaning it continues to follow patients who have already participated in earlier studies of DNL310. The goal is to gather more information about the treatment’s long-term effects and benefits for those living with MPS II. Participants will be involved in the study for several years, allowing researchers to collect comprehensive data on the treatment’s impact over time.